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The catalytic hydrodechlorination (HDC) technology exhibits great flexibility and safety under mild conditions, and shows extremely promising application prospects for the degradation of 4-Chlorophenol (4-CP). Prepare the N-doped phenolic resin carbon support (PMF) using phenol, melamine and formaldehyde as raw materials, and load Pd nanoparticles (NPs) on it. The XPS results indicate that the Pd/PMF-800 has a higher Pyridine-N (24.8%) and a higher Pd 0 /(Pd 2+ +Pd 0 ) ratio (65.4%). Moreover, the difference in electronegativity between the N atom and the resin carbon support enhances the binding energy between them. This enhancement promotes the nucleation of Pd NPs on the surface of the resin carbon support, thereby imparting higher stability to the Pd NPs. Due to these comprehensive advantages, Pd/PMF-800 has the highest dechlorination activity (k obs = 0.0594 min⁻¹) and stability (dechlorination rate is 91.56% after 5 cycle). Additionally, it also demonstrates efficient dehalogenation rates for 2-Chlorophenol and 4-Bromophenol. It can provide a catalyst that has high-efficiency dehalogenation performance, strong acid and alkali stability and adaptability, and can be recycled for the degradation of halogenated phenols in the environment.

4-chlorophenol (4-CP), a hydroxylated aromatic compound (HAC), is a recalcitrant and toxic organic pollutant found in industrial wastewater and various environmental media. In this paper, visible-light-activated photocatalysis using graphitic carbon nitride (GCN) was used to treat 4-CP in an aqueous media. Graphitic carbon nitride from different precursors (dicyanamide, urea, and melamine), as well as GCN/silver nanocomposites (AgBr, Ag3PO4, Ag2CrO4, and Ag), were successfully synthesized and characterized by BET, XRD, SEM, EDS, and UV-Vis DRS. The band gaps of the photocatalysts were estimated using the UV-Vis DRS characterization results and Tauc plots. The evaluation of the efficacy of the GCN-based catalysts in degrading 4-CP was conducted with different photoreactors such as a royal blue light-emitting diode (LED), a UV-A LED, LUZCHEM cool white lamps, and a solar simulator. The results showed that GCNs with royal blue LED can effectively degrade 4-CP from aqueous media. Among the different precursors, urea-derived GCN showed the best performance in degrading 4-CP due to its large surface area. GCN/0.3Ag2CrO4 nanocomposite showed a synergistic effect for the enhanced photocatalytic degradation of 4-CP. The degradation of 4-CP with a rate constant of 2.64 × 10−2 min−1 was achieved with a GCN/0.3Ag2CrO4 nanocomposite under royal blue LED irradiation.

Peroxidase-like based on double transition metals have higher catalytic activity and are considered to have great potential for application in the field of pollutant degradation. First, in this paper, a novel Fe 0 -doped three-dimensional porous Fe 0 @FeMn-NC-like peroxidase was synthesized by a simple one-step thermal reduction method. The doping of manganese was able to reduce part of the iron in Fe-Mn binary oxides to Fe 0 at high temperatures. In addition, Fe 0 @FeMn-NC has excellent peroxidase-like mimetic activity, and thus, it was used for the rapid degradation of p-chlorophenol (4-CP). During the degradation process, Fe 0 was able to rapidly replenish the constantly depleted Fe 2+ in the reaction system and brought in a large number of additional electrons. The ineffective decomposition of H 2 O 2 due to the use of H 2 O 2 as an electron donor in the reduction reactions from Fe 3+ to Fe 2+ and from Mn 3+ to Mn 2+ was avoided. Finally, based on the experimental results of LC-MS and combined with theoretical calculations, the degradation process of 4-CP was rationally analyzed, in which the intermediates were mainly p-chloro-catechol, p-chloro resorcinol, and p-benzoquinone. Fe 0 @FeMn-NC nano-enzymes have excellent catalytic activity as well as structural stability and perform well in the treatment of simulated wastewater containing a variety of phenolic pollutants as well as real chemical wastewater. It provides some insights and methods for the application of peroxidase-like enzymes in the degradation of organic pollutants.